Machine for producing tubes or other hollow cylindrical articles



y 13, 1952 H. HEIMANN 2,596,552

MACHINE FOR PRODUCING TUBES OR OTHER HOLLOW CYLINDRICAL ARTICLES 3Sheets-Sheet 1 Filed Oct. 24, 1944 2% w fig mm H R Q E H mm m mm m Q mm1% w mm hm Wm M fi II M \CHH.-- mm u- Q w INVENTOR Heinrwfi Hez'marzmATTORNEY May 13, 1952 H. HEIMANN 2,596,552

MACHINE FOR PRODUCING TUBES OR OTHER HOLLOW CYLINDRICAL ARTICLES FiledOct. 24, 1944 SSheets-Sheet 2 !NVENT OR Hemrwk Helm/an ATTORNEY y 13,1952 H. HEIMANN 2,596,552

MACHINE FOR PRODUCING TUBES 0R OTHER HOLLOW CYLINDRICAL ARTICLES FiledOct. 24, 1944 3 Shepts-Sheet 3 B I, 73 65 66@ 72 k C L 4? g; :2; 65-- gE mw V ATTORNEY Patented May 13, 1952 MACHINEIFOR PRODUCING TUBES OROTHER; HOLLOW CYLINDRICAL AR- TICLESJ HeinrichHeimann, NmYorkgMY.

Application October-24, 1944} Seri'alNo'. 560,174

8: Claims; (Cl; 29--343i1- This invention relates to an extrusionpressfor producing seamless tubes or'other hollow cylindrical articlesfrom metal or any other cleformable material.

The usual extrusion process for tubes, mostly performed in horizontalpresses. requires billets provided with a central axial hole whichzis'made either in advance, orby piercing insitu:

Furthermore such process requires equal resistance todeformationthroughout the cross sec-- tions of the billets, and aprecise alignment of extrusion ram andmandrel with billet container. anddie. (See e. g. Extrusion of Metals"- by Claude E. Pearson, 1944, p;1115.)

The main object of thepresentt invention is'a new machine for extrudingtubes and'other'hollow articles from solid imperforate'billets' which,in further distinction from the known production, need not be" passedthrough a" narrow gap between the Wall: of. the die openinganda mandrel.

In the new machine an imperforate billet; in

the mannerusual for producing rods, is extruded,

in the form of a rod; and thisro'd, directly behind the extrusion die,while being'lieldagainst'" rotation, is gripped by azseco'ndfnr.revolving; die rotating around. the axisrof the rod and'provi'ded. withmeans impelling and advancing the "surface layers of the rod with anaxial velocity greater: than the velocity of the rod at its pointofentrance into the rotating die. I

Thereby a flow of material, in accordance with; the law of continuity,ensues from the; core, of the rod to its surface,,. in an amountmakin'g'up for the difference of volume. between. the. outer layers of materialentering, the revolving, die with a relatively small axial velocity"and, th outer layers leaving the revolving, die with a relatively highaxial velocity.

By the so obtained quickenedaxialladvance'of the outer layers of the redthe latter is transformed into a tube.

In the revolvingdie, thus, afski1ming"action on the rod is performed.This, die, accordingly; will be called henceforth the skinni'ngdi'e:From the degree of difierence betweeni entrance velocity and exitvelocity ofth'e material.in* the skinning die depends, as stated above.thevamount of material flowing from thecore ofthe rod"to"itssurface and,therefore, the inner diameter of" the tube or hollow article tobeproduced:

By varying theR. P. M. oithe skinning; die'during the operation theinner diameterofthe body or article leaving the die canbe varied. accord2 wall thicknesses differing from beginning to the end of the extrusioncanbe produced. Evena hollowbody with completely closed front and rearends may be produced by temporarily diminishing'the R. P. M. of theskinning die according; to the condition that in the closed end zones ofthe article to be produced the exit velocity of the" material in theskinning die has to beeq-ual' to the entrance velocity i. e. to the rodextrusion'velocity.

From the foregoing it should appear clearly that, as hinted above;therodin the skinning diehas to-befirmly secured against rotation withthe latter. This can be done-by a separate grippi-ng head firmly securedagainst rotation or; if the skinning die is arranged directly behind theextrusion die, by the rigidly fixed extrusion die itself) in which therod cannot rotate due'to' its high friction against the surface of theextrusion die, so that the extrusion press functions as a feeding andgripping device:

It. is obvious'that a certain slip of material in the-skinning diecannot be avoided in spite of such friction and that therefore, the R.P. M. of theskinning di'e' have tobe increased accordingly to= producethe required axial flow of material.

T'owcreate the described quicker axial flow of theme-tonal the skinningdie can be formed in many diiferenti ways. The simplest way is to usearskinning diein. the form of a revolving nut, the; innerscrew threadsorriflings of which grip the non-revolving; material. and: drive itssurface layers'i-ina axialndirectioni with. a velocity depending uponthe pitch: of: the threads or riflings and. the-number oi revolutionsbut greater than. the extrusion velocity. Such a die may exert on. thesurfaceof the, red at relatively high friction in. peripheraldirection;

To reduce lthe friction the rotary skinning die aet upon the surface ofvthe rod by symmetrically arranged planetary pressure rollers. Theserollerscan be. arranged with their axes. skewed or oppositely inclinedto the. axis of the rod in a. manner similar to that. found intuberolling mills with non-planetary rollers. But these planetaryrollers. can also have their axes parallel to. the axis of" the rod and,in this case, are provided with male screw threads for creating theaxial. new" of material by the rolls rotating around theiraxes; andsimultaneously spinning around the-axisnf'therod.

Further objects of the invention Will be set! forth-in the-followingspecification with illustrati'vedrawings: In these drawings'severa'lembodi ingly, with the result theta;hollowarticlewitlr 58 ments of'apparatus forforming tubes or hollow bodies according to the new methodare shown Figure 4 shows in longitudinal section one embodiment of thedie set with ordinary rigidly fixed stationary extrusion die andrevolving skinning die in front of the container for the material;

Figure shows another embodiment of the die set in front of thecontainer, in longitudinal section;

Figure 6 shows a further embodiment of the die set in front of thecontainer, in longitudinal section. V A die set A in front of the fronthead B of the extrusion press (Figures 1 and 2) is arranged in thecenter of the press and can be shifted'in axial direction for reasonsexplained further below.

On the rear side of the front head B of the press is arranged acontainer C for the billet to be worked upon. In the rear head D of thepress frame,'connected to the front head B by the well known strainrodsE, is rigidly arranged the stationary'hydrau lic press cylinder F.The die set A, as shown'in Figures 3 and 4, comprises an eX- trusiondieIn rigidly fixed in a die holder ring 1 l which itself is abuttedagainst a ring-like bolster body l2 which, with its front wall [3,bottom [4 and side walls [5 and I6 (see Figures -1 and 2) forms a rigidframe.

In front of the extrusion die If! and inside the bolster body I2 isarranged the skinning die I! provided with internal screw threads I 8 ofthe appropriate pitch dependingupon the R. P. M. of the skinning die.The skinning die is e. g. screwed into the tube like rotary die holderIS in such a way that the reaction of the work piece on such die,accelerating axially the surface layers of the metaLtends to tightensuch screw connection. The die holder I9 is formed as a hollow shaftmounted in the cylindrical bolster body I? bearing 24a, in the frontbore |3a of the die set' frame A.

As can be seen from Figure 4 the press ram 25 extrudes the imperforatebillet 26 by means of the follower disk 2'! through the rigidly fixedstationary die In in the form of a rod-like body 28 which, by the rotarynut-like skinning die I! with screw threads l8 accelerating the outerlayers of the material, is then deformed into a hollow tubelike body 28,whose wall thickness can be changed by changing the speed of the motor24, or by changing the ratio of the gearing 22, 23. The die set A has tobe securely locked against the press head B during the extrusionprocess. This can be done by special means shown in-Figures 4 2 and 3and described in greater detail further below.

To shift the die set A in axial direction its frame is provided withbrackets 30, 3!, 32 and 33, for rollers or wheels 353', 31', 32', 33',running on rails 34 and 35 respectively, arranged in front of the presshead B. In the outward or retracted position of theset A the notextrusible end or lost head of the billet can be removed from thecontainer C. During the extrusion the die set has to be reliably lockedto the front head B. This is done, f. i. (see Figures 2 and 3), bylocking spindles 3G and 31 turnable in bores of the front head 'B andprovided with oblong head 38 and 39. The spindles 35 and 37 go freelythrough oblong bores 36', 31' of lugs 40 and 4| of the die set frame.

When the longitudinal axes of the spindle heads 38' and 39 coincide withthe longitudinal axes of the bores 36', 3'! said heads pass freelythrough said bores, and the die set A can be retracted in axialdirection from the front head B of the press. If the spindles 36 and 31are turned around the die set A is locked with the front head B of thepress by said spindle heads 38, 39.

If the front surfaces of the lugs 40 and 4| are sloped, and the abuttingsurfaces of the heads 38 and. 39 are sloped correspondingly, then, byturning the spindles 36 and 31, axial pressure, 1. e. a wedge effect, isexerted which assures tight locking of the die set A with the frontsurface of the presshead B. I 1

The spindles 36, 31 can beturned through 90 by pinions 42 and 43 (Figure2) keyed on the free ends of these spindles and meshing with racks 44and 45 connected with pistons in hydraulic control cylinders 46 and 47,symmetrically arranged on opposite sides of the press head B.

The hydraulic cylinder F for extruding the from a furnace ona conveyor48, shown only the hydraulic cylinder F is a'diiferen'tialpiston.

The differential shoulder 5| of the piston is'kept constantly undermedium pressure by a fluid en tering this cylinder through a connection52 at its front end. The rear end of the cylinder can be'broughtselectively'under low pressure, mediumrpressure, or high pressure of afluid, .f. 1. oil, by connecting an inlet 53 with a low pressure source,or an inlet 54 with a medium pressure source or an inlet 55 with a highpressure source. None of these pressure sources is shown. Thecontrolling means of these connections, f. i. electrically controlledvalves are of well known type and, therefore, need not be describedhere. When the rear surface 56 of thepiston is under low pressure theforce exerted by the medium pressure on the shoulder 5| overcomes theforceexerted'on'the surface 56 by the low pressure so that the piston 49ismoved backward,-i. e.

to the right, into its end position formaking posfriction of the pistonin the cylinder and the1 frictionof the billet on its'supportingsurface.

so that the billet is pushed into the container 0 2 nd: aga n t he.eitheleeked die a.

When; the med um Press he pi es; c anged ta h.

forc s exert on s r c it to attained-1a.

w t e r quire xi l; r .09. y throu h the. p n ng. fzthe statio ary-QXHHQQR. ie. n. intohe. m u h ofth ro ary sk nning. ie: L

This arrangem nt. requi es r lati e x ens; hyd a l c. li d r: F ut simpifies. the

he billet o t e pr ssand. nt he Qemain r C and makes for an easyassemblydis.- mantling of container and press head. Furthermore, thepressure, against which the rear side, i. e. the right hand end, of thepiston has to be sealed equals only, the; difference between high pres eand medium ressure w i e at ire-front or left hand end the piston has,only to. be, sealed.

on a shaft 59 rotatably adjustable in bearingsof frame, 51. e. g. by alever (not shown) attachable to the square end 60 of the shaft. Theeccentric roll 58 can be locked in any position by set screws GI and 62.

As can be seen from Figure 4 the product, in the form of the tube likebody 29 leaving the skinning die because of the action of the screwthreads I8, has screw like threads or welts on its outer surface. If aneven and smooth cylindrical outer surface is required the die setaccording to Figure 5 may be used.

In this embodiment the extrusion die 6 l, rigidly locked with the frontsurface of the container C, is held in the holder 62, which is arrangedin the rigid frame 63 aligned with container C. The skinning die 64, ofthe same construction as in Figure 4, is screwed into the holder 65rotatable by means of wheels 66, 61 by an electric motor (not shown)arranged in the die set frame.

A radial ball bearing 68 and a thrust ball bearing 69 ensure the exactconcentricity of holder 65 and frame 63. In front of the rotary skinningdie 64 is arranged a second fixed die 10 whose diameter equals, or isslightly smaller than, the smallest diameter of the screw threads of theskinning die 64. This rigid fixed die 10 is arranged in a die holder 1|aligned in the rigid cover plate 12 screwed to a flange '13 of the dieset housing 63.

In this way the screw threads on the tubular product leaving theskinning die 64 are levelled or ironed out so that the surface of thetube produced is smooth, cylindrical and even. The arrangement of thefixed die 10 in front of the skinning die 64 has the further advantagethat the extruded article or product is held against rotation by saiddie 10 in addition to being held by the die 6|.

The arrangement of the die set according to Figure 6 is similar to thatof Figure 4, with the difference that instead of the skinning dieprovided with internal threads or riflings are pro vided two or morerollers 14, 15 having on the surface threads 16 and 11 of appropriatepitch. These rollers are rotatably mounted with their axes l8 and 19 inbearings of the rotatable frame 80.

6 frame throu h; wh sebcrett the r h llow product is extruded; is; abeted; a ainst.

the ri id. housing. .2. o the fixed die it be radial thrust ball.bearings. 84 and. 8 5:, and. is; provided witha pinion 8.6,. driven bymeans. of; a gearat. e. sby: an. eetrom-otor (not: shcwnh.

tis abtiq s from the forego ng that: bit revolw is. the: ame 1 herollers Hr and: 1:5. are driven: in. a p an ary manner ar undttheextruded;

1 pressed axiallx through t e space between;

al r l ers and; at the same time the latter 110-- tatet rouu the raxesbecausecr the friction of; the ro lers. on arti le: 2.90. Thereby:the. surface ayers: f. the extruded; article are impelled with.

1- n axialx velocity greater: than the am xelqci r of. the. xtrudedbadyadvan ins; throu h ticn 8 so that again. the effect. asdeserihdahora, akesnla a- Th mh s tw en he die; the. surface or the. extrudedarticle isdminishediheraby'themollerm and the: slipof; saidarticlerelatiue to thaskinning dieisadinii. li d cerr snondinelxi netQfiEi'snre; 6: the. rollers. 14. which. are.- lzarallelr to the axis of:

thepress; may harepl'aeed: by skewed: unthreaded l ers which. act; in.the. manner well," known. in; the art of producing tubes and, thereforeneed:

notbe shown crdescribedin-detailjl Whatl claiming.

1. A machine for making hollow bodies from a solid billet of metal orother plastically deformable material, comprising an extrusion pressprovided with an extrusion die and a rotating die arranged directlybehind. the extrusion die, and means for maintaining the rotating dieaxially fixed relatively to the extrusion die. said rotating die havingportions inclined to its center line and positioned to exert pressure onthe surface of the extruded rod and means for rotating the rotating dieat a sufficient speed to impart an axial velocity to the extruded rodexceeding the velocity of extrusion.

2. A machine as set forth in claim 1 wherein the rotating die is in theform of a nut the threads of which constitute the portions inclined toits center line.

3. A machine of the character described and as set forth in claim 1, therotating die comprising a power-driven rotary frame with threadedrollers arranged parallel to the center line of the frame and engagingwith their threads the surface of the extruded rod under pressure and atan axial velocity surpassing the exit velocity of the rod from theextrusion die.

4. A machine as set forth in claim 1 wherein the extrusion press isprovided with a movable frame which is separable from but locked to theother parts of the press and wherein the extrusion die and the rotatingdie are fixedly connected to each other on said frame.

5. A machine for making hollow bodies from a solid billet of metal orother plastically deformable material, comprising an extrusion pressprovided with an extrusion die; a rotating die ar ranged directly behindthe extrusion die and integrally connected to it in axial direction,said rotating die having portions inclined to its center line and actingwith pressure on the surface of the extruded rod at an axial velocitysurpassing the extrusion velocity; a non-rotating unt-hread ed diearranged adjacent the exit of the rotating die and acting with uniformpressure around the surface of the hollow body leaving the rotating die.

6. A machine for making hollow bodies from a 7 solid billet of metal orother'plastically deformable material, comprising an extrusion pressprovided with a stationary frame and an extrusion die and rotating die,one arranged directly adjacent the other andboth integrally connected toeach other in axial direction, the rotating die having portions inclinedto its center line and acting with pressure on the surface of theextruded rod at an axial velocity surpassing the velocity of the rodleaving the extrusion die, a movable frame for holding both theextrusion die and the rotating die, said stationary frame being providedwith spindles adapted to be turned at an angle of approximately 90, saidspindles having oblong heads corresponding to oblong holes in themovable frame so that in one end position the oblong heads of thespindles are aligned with the oblong heads of the frame, while in theother end position they lock themovable frame of the die to the frame ofthe extrusion press.

I 7'. A machine as set forth in claim 6, the heads of the lockingspindles being provided with wedge surfaces co-operating withcorresponding wedge surfaces on the frame of the extrusion press andbeing turned selectively into and out of alignment with the oblong holesin the frame by hydraulic cylinders.

8. A machinefor making hollow bodies from a solid billet of metal orother plastically deformable material, comprising an extrusion pressprovided with anextrusion die and an axially closely adjacent'to itarranged rotating die, said extrusion press being further provided witha ram driven by a differential piston, the side of said piston forforward stroke being selectively connected by controlling valves tothree hydraulic conduits for low, medium and high pressure,respectively, while the opposite side of said piston is permanentlyconnected to the conduit of medium pressure.

Hm ICH HEIMA NN.

REFERENCES CITED 7 The following references are of recordin the file ofthis patent:

UNITED STATES PATENTS Great Britain r i Jan. 22, 1920

